Supercharger drive



June 1, 1937. E. J. SMITH ET AL SUPERCHARGER DRIVE Filed Oct. 18, 1934Sheets-Sheet 1 I. 6 5 w z 4 5 .H 4 z z mm m 4 E W 3 n M Z w. @W

4 HE W r M6 June 1, 1937. E. J. SMITH El AL SUPERCHARGEIR DRVIVE FiledOct. 18, 1954 s Sheets-Sheet 2 June 1, 1937. E. .1. SMITH ET ALSUPERCHARGER DRIVE H 3 H v a m% H ms 0 M W n t 3 A D mm 3 .5 w w l m o td y w. a

Patented June 1, 1937 UNITED srATEs surcacrmmna DRIVE Edward J. Smithand l i zene s. Bush, st. Louis,

Application October 18,

4 Claims.

This invention relates to improvements in supercharger drives, and moreparticularly to a variable speed drive adapted for the transmission ofdriving-energy from an internal combustion 5 engine to a supercharger.therefor, the device herein disclosed being admirably suited, because ofcompactness and rigidity of construction, for

, use with airplane motors and superchargers With the advent of improvedfacilities for high altitude flying there has developed an increasedneed for a more adequate control of output of superchargers, so as tocare more eflicientiyfor the wider range of variation inthe manifoldpressures normally incident to commercial flying at altitudes varyingfrom zero to, say, thirty thousand feet or over. It is customary inprevailing types of aircraft engines to employ a supercharger ofcentrifugal type, driven from the engine directly, or bythe interventionof a go train of gears. Because of the necessary minimization of weightand space requirement, it has heretofore been impractical successfullyto employ a speed change transmission 'of ordinary sembly areenabled, inspite of a high rate of rotation, successfully to resist the tremendouscentrifugal forces encountered.

Yet another object of the invention is attained in an arrangementpermitting a ready selection of and one of a plurality of blower-drivingratios while the engine is in operation at speed,

' and 'yet obviating any hazardous shearing to a change of drivingratio. Still another object of the invention is at-; tained in a compactspeed change transmission 60 for the purpose noted, and which isparticularly which is further particularly adapted to a combination withsupercharger driving assemblies for internal combustion enginesgenerally.

The foregoing and other objects will more clearly appear from thefollowing detailed destrictions, the rapidly rotating parts of theasstresses or adverse torque conditions incident..

adapted for remote mechanical control, and

1934, Serial No. 748,824

scription of a preferred embodiment of the invention, considered inconnection with the accompanying drawings, in which:

Fig. 1 is a vertical sectional elevation through an aircraft engine ofradial type, into which is 5 built a supercharger and variable speeddrive constructed in accordance with the principles of the presentinvention; Fig. 2 is an enlarged vertical section through thesupercharger and drive assembly asvviewed along line 2-2 of Fig. 4; Fig.3 is a vertical sectional elevation through the blower drive assembly,but illustrating other of the speed control elements in a differentposition than those shown by Fig 2; Fig. 4 is a sectional elevationalong a planeat right angles to the axis of the rotation, and as viewedalong line 4-4 of Fig. 2, illustrating particularly a preferredarrangement of the gear elements of .the variable speed drive; Fig. 5 isa fragmentary, partly diagrammatic showing of certain of the controlelements; Fig. 6 is a vertical sectional elevation taken along line 6-45of Fig. 5, and further illustrating several of the control elementsshown by Fig. 5, and Fig. '7 is a detailed view taken along the curvedplane 1-! of Fig. 5, 25 and further illustrating a detail of the controlarrangement.

Referring now by characters of reference to the drawings, there is shownby Fig. 1, an exemplifying adaptation of the present invention to 30 anaircraft motor III of radial type. The engine cylinders, one of which isshown at H, each serves for the operative reception of a power pistonl2. The forward end of the engine is characterized by a crankshaftprojection I3 serving to receive the usual propeller hub or boss (notshown), connection being made to the crank from each piston, as by aconnecting rod l4. Rearwardly of the engine is located a carburetor l5provided with a throttle (not shown) I which may be of any suitable orusual type controlled by a throttle control rod l6.

In accordance with prevailing practice, or as preferred, thesupercharger is arrangedthrough connections (not shown) to augment theintake air pressure, the supercharger assembly being provided with aninlet passage l8 directed into the central'area of a centrifugalimpeller or blower element l9. Due to the centrifugal force imparted tothe air entering the center of the rotor or impeller IS, the air isdischarged peripherally into a volute 20, whence the air, at a volumeand pressure proportionate to the speed of the impeller, is directedinto the carburetor and/or manifold of the engine.

. gears 4|.

plungers and surface 39 is such that these parts .constitute a gearclutch, and since relatively dis- The impeller l9 derives its energy ofrotation from the engine through a shaft 2| provided with a splineddriving end 22 (Fig. l), engaging a correspondingly splined socketportion 23 at the end of the crankshaft |3.

Referring now more particularly to the elements and structure of thevariable speed drive,

the drive shaft 2| is journalled, preferably in an anti-friction bearingexemplified at 24 and mounted in' a cup or recess 25 therefor, formed aspart of a detachable wall portion 26 of an oiland dust-proof housing 21for the variable speed driving elements, this housing being integralwith or formed as a part of the fan or blower volute or enclosure.

' Just inwardly of the wall 25 is a gear 28 secured as by a key to theshaft 2|, the gear 28 enmeshing with a plurality, (shown as 4) ofpinions 29, the axes of the pinions being evenly angularly spaced aboutthe preferably circular housing 21. Each of the pinions 29 is journalledat its outer end in anti-friction preferably ball bearings 30, and atits inner end is provided with a shoulder 3| extending in journallingrelation into a recess therefor in an adjacent gear hereinafterdescribed. Each of the pinions 29 is further provided with an axialaperture 32 which is internally splined to receive external splines 33of a gear clutch head 34, the axial aperture 32 of each of the pinions29 serving further to house a compression spring 35 engaging at one endthe bottom of a socket therefor in the pinion, and at the opposite endbearing upon the splined head 33.

' Each of the gear clutch heads 34 embodies one or more spring pressed,radially movable plungers 36 (Fig. 4) each mounted within a radialsocket 31 so as to be urged outwardly by the plunger spring 38 intoyieldable driving relation with an internally scalloped surface 39formed within an axial bore 49 of each of the As will appear, therelation "of the placeable under excess torque, also serve as anoverload release. The latter gears are, journalledexternally inanti-friction bearings fl and are laterally recessed to receive injournalling relation the projections 3| of the adjacent pinions 29. Thegroup of gears 4| are of relative larger diameter than the gears 29, arespaced 180" apart, and enmesh in turn with a somewhat smaller gear 43.The latter gear is formed as a part of or secured to a sleeve or hollowshaft 44 extending from the gear 43 along and overlying the shaft 2|,the sleeve being journalled thereon but not secured thereto. The sleeve44 serves as a mounting for the impeller |9 which is secured thereto asby a key 45.

For purposes of control actuation, each of the driving heads 34 is.provided at its "inner end with a ball head 50, engaged by the socketedend of an arm 5|, so pivoted to an, arm 5211s to constitute a togglelinkage. The opposite end of arm 52 is pivoted as at 53 to the innerwall of the case 21. Pivotally connected for centering the toggle is aplunger 54, operating through a slot 55 in a bracket 55 projectinginwardly of the adjacent case wall. A spring 51 tends to bias theplunger 54 inwardly along the radius of the assembly and in a-directiontending to break the toggle 5|52, and to maintain the inner end of therelated plunger 54 in engagement with a groove 58 of a rotatable controlcam 59, (Figs. 5 and 6). The cam 59 is provided with a pair of lowpoints 30, which are diametrically opposite each other, and a spaced butcorrespondingly opposed pair of low points 6|, for a purpose hereinafterdescribed. For actuation of the cam 59 this element is extended to forma gear, or a toothed sector portion 62, enmeshing with a fragmentarygear 63, pivoted at 54 and engaged upon its opposite tooth end by acontrol pinion 55. This pinion is secured to a rotatable control shaft66, which extends to a convenient point of access, say to the controlcockpit or the pilot's instrument board.

It will be observed that the action of cam 53 when rotated to permit theends of plungers 54 to engage the low points such as 60, is to permitthe springs 51 to retract the plungers 54, decentering the toggles 5l-52and actuating the driving heads 34 inwardly to a position of operativeengagement with the gears 4|. In this position of the heads 34, thegears 4| are directly connected to the pinions 29 through the splinedelements 32-33, the action of the springs 35 being to assist thisoperative connection of the gear-clutch elements.

Referring now to Fig. 3 of the drawings, which is taken on a section ata right angle to that of Fig. 2, it will appear that the gear 23, whichis secured to shaft 2|, enmeshes with two other diametrally opposedpinions 29, which, for convenience of representation, are shown as beingof the same diameter as and substantially identical with the pairthereof illustrated by Fig. 2, and are similarly equipped with theaxially displaceable driving heads 33 and coacting control elements. Thegear-clutch heads of Fig. 3 are however movable into driving engagementwith a pair of diametrally opposed gears 14, each of which is provided,similarly to the gears 4|, with an axial bore II and an indented orscalloped internal surface 12 for the reception of the plungers 36 ofthe driving heads 34. The arrangement of gears I9, similarly to that ofthe gears 4|, is planetary, except for the fact that their axes arestationary. The gears 13 engage a drive pinion 13 which, like the gear43, is formed as a part of or secured to the sleeve 44 rotatably mountedupon the shaft 2|.. The control elements for actuating the gear-clutchheads 34 into and out of engagement with the portion 12 of gears III,are or may be the same as heretofore described for clutching'the gears4|.

It will have appeared from a comparison of Figs. 2 and 3 that when thetoggles 5|52 controlling the operative selection of a given set ofgears, are centered as shown by Fig. 3, the gearclutch heads areretracted out of operative engagement with the corresponding gears,while, when the toggles are decentered, as shown by Fig. 2, a given setof gears is operatively connected to the companion pinion 29.

It will appear from Fig. 4 that, for a given speed of shaft 2|, thehighest driving ratio is attained when driving of the superchargerimpeller takes place through shaft 2|, gear 23, the pinions 29associated with the gears II, and thence to pinion 13. A lower ,orintermediate ratio is attained in the example shown, when driving takesplace through shaft 2|, gear 23,

'gears 4| and the associated pinions, thence to gear 43 and the impellermounting sleeve 44. In both high and intermediate settings, these groupsof gears each. constitutes an overdrive between the shaft 2| and theimpeller.

A still lower driving rate or ratio is provided engage low points on thecam 59. However, as

for by an arrangement which may. be referred to as a direct drive, andwhich is attainable through axial movement of the sleeve 40 a smalldistance to the right (Fig. 2), this control movejections 16 formed onan internal face of a nose element Tl carried by the end of the sleeve44. The shaft 2! is provided with an outwardly projecting stud l8threaded to receive at its outer end a cap 19. .The element 'I'! isprovided with an axial chamber 80, serving to receive and constituteabutments and anchorage for a spring 8|. A threaded collar 82 externallyengages the nose element 11 and may be pinned thereto by a member 83.The arrangement of the spring and anchorage is such that the sleeve andimpeller are biased to the right (Fig. 2) along the shaft.

The impeller is provided near its opposite axial portion with an annularrecess 84 which, in operation, rotates about a stationary interfittingelement 85. The latter element is provided with plungers 86 of a size towork through suitable apertures therefor in the wall of the case 2?. sothat the inner ends of the plungers 8t bear against a lateral face ofcam 59. The cam is provided with, say, a pair of diametrally opposedrecesses 8?; one of which is shown in detail in Fig. '7, so that as thecam 59 is rotated to a. predetermined position, the plungers 8t permitthe sleeve and impeller assembly under the influence of spring M, tomove a sumcient distance along the axis to permit interengagement ofpro- .iections l6 and recesses 15. It will appear that in this position,the shaft 2i serves directly to drive the impeller at a correspondingrate of rotation.

Assurance against concurrent engagement of the gearing of two ratios ata time is, of course, precluded by the spaced relation of the low points6d and ti on cam 5%, with respect to the groups of plungers, while therecesses 8i, corresponding to direct drive position, are likewiseangularly displaced with respect to the other low points.

Referring further to, the relation .of the controls and control parts,including the cam as. it will appear from the legends of Fig. 5 thatwhen the element 63 is actuated counterclockwise from the positionshown, through a distance sufflcient to permit interengagement of theplungers he with the recesses 8?, the interengagement of projections Itand recesses 15 causes a direct drive of the blower by shaft if at a.low speed.

As the element 63 is moved clockwise (Fig. 5)

to the position of the parts shown, the pair of plungers 54 appearing inFig. 2, will be permitted to enter the low points 60 of cam 5Q,decentering one pair of the toggles 5i-52, causing springs '35 and 51 tocoact in displacing the driving heads 34 into operative connection withthe gears iii to cause, by means described, a setting of the drivingelements in the intermediate or second speed position. It will have beenobserved that the spacing of the low points and recesses of cam 59,considered in respect to the several control plungers, is such that aneutral position is attained between the low speed and second speedpositions.

Y Assuming now that the'member 6331s actuated, through pinion. 55, meclockwise direction (Fig. 5), a neutral position is ,first encounteredin which neither pair of the plungers 54 or' 85 gear 63 is actuatedfurther in a clockwise direction, low points 6! move counterclockwise toreceive the pair of plungers 54 shown by Fig. 3,

, causing, by agencies described, the driving heads 34 to enter andoperatively" to engage the gears 10, in which position the highest gearratio exists between shaft 2i and the impeller i! of the blower.

It will have been observed from the description of parts thattheplanetary arrangement of gears, best shown by Fig. 4, is particularlyeconomical of space and reduces the requisite diameter or parts and thecase, while the nested relation of companion gears such as 29 and M,"and the manner of journalling the gears 4| and 10 as by internallyprojecting elements of the .case, makes for economy of axial dimension,it being noted that both sets of gears 10 and iii are Journalled in partin the pr6jections'90 carried by or between the wall elements of thecase 27. I

It will further appear from the foregoing description that the variablespeed supercharger of the present invention is constructed so as morethan adequately to resist the unusual centrifugal forces encounteredbecause of the high speeds of rotation, and that the manner ofinterconnecting the constantly-driven with the intermittentlydrivengearing is such that, until the initial inertia effects are overcome,the plungers 3t'may first yieldably engage the scalloped internalsurfaces of the related gears, and thus prevent any harmful effectsincident to the unusual shearing stresses heretofore encountered. Byvirtue of these advantages, and in keeping with others heretoforeexpressed and implied, the assefiibly stood solely in a descriptive andnot in a limiting sense, since numerous changes may be made in theparts, their arrangement and combinations,

without departing from the full intended scope of the'invention asdefined by the appended.

hollow shaft, a drive pinion on the hollow shaft,-

a pinion on the drive shaft, a train of gears including the saidpinions, control means for .selectively rendering the gear trainoperative d inoperative, including gear clutches internally of certainof the gears of the train, a. separate clutch formedby interfittingelements on, and constituting a. direct-drive connection betweensaid-shafts, the last said clutch elements being operable by relativeaxial displacement of the shafts, said control means including elementsselectively operable to shift one of said shafts and make and break saidshaft connection.

}'-2. An engine-blower drive including a hollow impeller shaft; a driveshaft on which the impeller shaft is rotatably and shiftably mounted,

operable internally of,'and arranged selectively v to connect anddisconnect the said companion gears, a control cam, radially arrangedplungers coacting with the cam to actuate the gear clutches, and meanscoacting with the cam relatively to shift the impeller and drive shaftsinto and out of direct operative connection.

3. A supercharger drive assembly including a hollow impeller shaft, 9.,drive shaft on which the hollow shaft is mounted, a. pinion on each ofsaid shafts, a pair of coaxial gears, each enmeshing with one of saidpinions, an axial passage in each of the coaxial gears, a gearclutchingelement internally of the gears and movable along said passage foroperatively connecting and disconnecting the coaxial gears, meansassociated with the clutching element and one of the gears, constitutingan overload driving connection, means exteriorly engaging the coaxialpassage therethrough, manual control means for the gear-clutchingelement arranged to establish a predetermined driving ratio between theimpeller shaft andthe drive shaft, and a clutch characterized byelements carried by the hollow shaft and drive shaft, said clutch beingassociated with said manual control means, and adapted selectively topermit a direct-drive connection between the impeller and drive shafts.

4. In an engine-blower drive assembly, a housing, a partition thereindividing the housing into compartments, a hollow shaft for carrying ablower element, operable in one of said compartments, said shaftincluding an axial extension projecting into an adjacent compartment ofthe housing, a drive shaft projecting into the last said compartment,and carrying the hollow, shaft, interfltting portions on the shafts, andmeans coacting therewith relatively to displace the said shafts intodirect operative connection, speed-change gearing in the last saidcompartment including a blower drive pinion on the said extension, asecond pinion adjacently located on the drive shaft, a train ofenmeshing gears in the last said compartment of the housing andincluding, in addition to the blower drive pinion and drive shaftpinion, a pair of coaxial gears, each engaging one of said pinions andadapted to establish a predetermined gear ratio therebetween, a gearclutch operable axially and internally of the said paired gears, andadapted selectively to connect and disconnect the paired gears, a manualcontrol element accessible exteriorly of the housing, and means fortranslating the movement of the control element for actuation of thesaid gear clutch, said means including elements for selectivelytranslating a movement of the control element for relatively shiftingsaid shafts.

EDWARD J. SMITH. EUGENE S. BUSH.

